1. Field of the Invention
This invention relates to an improved angled rotating surgical instrument. More particularly, this invention relates to an angled rotating surgical instrument wherein suction or aspiration may be effectively applied to the surgical site.
2. Discussion of the Prior Art
U.S. Pat. No. 4,646,738 to Trott, assigned to the assignee of the present application, shows a rotary surgical tool wherein a surgical cutter is mounted for rotation at the end of an angled, elongated rigid sheath. The cutter is driven by a flexible torque-transmitting member rotating within the sheath. A proximal end of the sheath is mounted to a housing of a motor, typically disposed in a handpiece. The motor is coupled to the torque-transmitting member to drive the rotary cutter. The sheath has a bend near its distal tip which allows the surgeon access to several different portions of the surgical site through a single incision. Such bent or angled surgical instruments are becoming increasingly popular.
In order that the torque-transmitting member can drive the cutter while extending around the bend in the sheath, the torque-transmitting member must be freely flexible. According to the Trott invention, the torque-transmitting member comprises three concentric flexible tubular spring-like members. Each of the flexible tubular members is a continuous spiral-wrapped stainless steel wire of generally flat cross-section. The central of the three concentric members is wound with the opposite hand with respect to the hand of the inner and outer members, so that upon application of torque, the assembly tends to tighten upon itself. The three concentric members are secured to one another at their ends by spot welding or a like expedient. The disclosure in the Trott patent is expressly incorporated herein in its entirety by this reference.
Another generally relevant device is shown in European Patent Application No. 445,981 of Krause et al, the disclosure in which, and in any U.S. counterpart patent, is expressly incorporated herein in its entirety by this reference. In Krause et al, a flexible torque-transmitting member for a surgical instrument having an angled probe is provided by forming a number of opposed rows of interdigitated circumferential slits extending through the wall of the tubular metallic member, or by drilling a number of offset rows of holes therethrough.
In order to remove debris from the surgical site, it is desirable to apply suction or aspiration to the proximal end of the instrument, the suction or aspiration being effectively conveyed to the surgical site by way of the lumen of the tubular torque-transmitting member. In the Trott device, the fact that the torque-transmitting member comprises three concentric spiral-wrapped members allows substantial suction or aspiration to be transmitted from the proximal end to the distal tip of the instrument. However, some leakage takes place between the substantially circumferential slits formed between the adjacent spiral-wrapped wire sections, so that improvement in the efficiency of transmission of the suction or aspiration would be desirable.
In the Krause et al device, the slits or holes in the torque-transmitting member may be filled with a silicone rubber or other pliable material to permit the necessary flexibility yet allow the suction or aspiration to be effectively conveyed to the distal tip of the instrument. Such pliant plugs tend to fall out of the slits, destroying their beneficial effect.
Other generally related subject matter is shown in U.S. Pat. No. 4,858,897 to Irifune showing a spring which might be used as a flexible tension member within a sheath in an instrument of the type shown in the Trott patent. The Irifune spring would also require protection against loss of suction as in the case of the Krause et al European patent. U.S. Pat. No. 4,576,772 to Carpenter shows a fluid-tight catheter having notches cut in its surface to facilitate bending. German OS 3,219,169 of Nagel et al apparently shows various ways in which a tubular member may be perforated or slit to impart flexibility thereto. If the Nagel et al device were used as a torque-transmitting element in a probe, suction or aspiration applied to one end thereof would not be effectively transmitted to the other end.